fix: preserve exception cause in error handling paths

[chenjunwenhao]

Summary

Several catch blocks throughout the codebase were silently discarding the original exception when reporting errors through ErrorReporter. This made debugging extremely difficult because the root cause was lost from the exception chain.

Root Cause

The ErrorReporter interface has two report overloads:

• report(Object catchObj, String errorCode, String reason) — preserves the exception as catchObj, which becomes the cause of the resulting QLRuntimeException
• report(String errorCode, String reason) — passes null as catchObj, losing the original exception

Multiple catch blocks were using the second overload, causing the caught exception to be completely discarded.

Fixes

File	Issue
NewInstanceInstruction.java	catch (Exception e) didn't pass e to errorReporter.report()
NewFilledInstanceInstruction.java	catch (Exception e) didn't pass e to errorReporter.report()
ForEachInstruction.java	catch (UserDefineException e) and catch (Throwable t) didn't pass exceptions
ReflectLoader.unwrapMethodInvokeEx()	IllegalArgumentException branch used reportFormat (no cause) instead of reportFormatWithCatch — affects 5 call sites
ThrowUtils.reportUserDefinedException()	UserDefineException not passed as catchObj — affects 6 call sites
Express4Runner.parseToDefinitionWithCache()	e.getCause() can be null (e.g., InterruptedException), causing new RuntimeException(null)

Tests

• Added exceptionCausePreservedTest in NewInstanceInstructionTest — verifies that InstantiationException (from instantiating an interface) is preserved as the cause
• Added parseToDefinitionWithCacheInvalidScriptTest in Express4RunnerTest — verifies error propagation for invalid scripts
• Added methodInvokeWrongArgTypeCausePreservedTest in Express4RunnerTest — verifies IllegalArgumentException is preserved when calling a method with wrong argument types
• Fixed MockErrorReporter to propagate catchObj (was hardcoded to null), enabling proper test verification

Test plan

• New unit tests verify getCause() returns the original exception
• Existing tests continue to pass (the MockErrorReporter fix is backward-compatible since catchObj is only used for initCause when it's a Throwable)
• CI pipeline validates full test suite

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