Reduce memory taken during compilation

[Nadeeshan96]

Purpose

Describe the problems, issues, or needs driving this feature/fix and include links to related issues.

This PR reduces the memory taken during compilation by means of the following.

1. Cleans up the BIR after the code generation phase.
2. Do not cache the TextDocument instance of dependent modules.
3. Remove BLangPackages of dependent modules after the code generation phase.

Fixes #41384
Fixes #41407

Approach

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Samples

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Remarks

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With Ballerina 2201.7.3 version without these changes the following code took about 900 MB memory for the heap at average when compiling the code for the first time.

import ballerina/io as _;
import ballerinax/health.fhir.r4 as _;
import ballerinax/health.fhir.r4.international401 as _;
import ballerinax/health.hl7v2 as _;
import ballerinax/health.hl7v2.utils.v2tofhirr4 as _;
import ballerinax/health.hl7v23 as _;
import ballerinax/health.hl7v2commons as _;

public function main() returns error? {}

With these changes introduced on top of that it takes about 700 MB memory for the heap at average when compiling the code for the first time.

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (7d548e5) 76.71% compared to head (68d25fa) 76.72%.
Report is 1 commits behind head on master.

Files	Patch %	Lines
...allerinalang/compiler/bir/codegen/JvmValueGen.java	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master   #41510   +/-   ##
=========================================
  Coverage     76.71%   76.72%           
+ Complexity    52667    52662    -5     
=========================================
  Files          2880     2879    -1     
  Lines        198580   198566   -14     
  Branches      25801    25797    -4     
=========================================
+ Hits         152334   152342    +8     
+ Misses        37812    37789   -23     
- Partials       8434     8435    +1     

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[HindujaB]

LGTM

[warunalakshitha]

LGTM