feat: allow to skip invalid assert conditions

[medcl]

This pull request includes several changes to improve error handling and reporting in the load testing framework. The most important changes include adding a new configuration option to skip invalid assertions, updating the statistics structure to differentiate between different types of assertion errors, and adding validation for requests during the warmup phase.

Closes #5

Improvements to error handling:

• domain.go: Added SkipInvalidAssert field to RunnerConfig struct to allow skipping invalid assertions.

Updates to statistics reporting:

• loader.go: Changed NumInvalid to NumAssertInvalid and added NumAssertSkipped in LoadStats struct to better categorize assertion errors.
• loader.go: Updated error counting logic in doRequest function to increment NumAssertSkipped if SkipInvalidAssert is enabled and NumAssertInvalid otherwise. [1] [2]

Request validation:

• loader.go: Added request validation in Warmup function to log and panic on invalid requests.

Updates to main loader logic:

• main.go: Updated startLoader and runLoaderConfig functions to handle new statistics fields and print detailed assertion error counts. [1] [2] [3]

[medcl]

Depends on : infinilabs/framework#7

[SteveLauC]

Verified that this patch implements the feature requested in #5:

[12-12 09:29:51] [ERR] [loader.go:486] invalid request: missing required Host header in request
panic: invalid request

goroutine 67 [running]:
main.(*LoadGenerator).Warmup(0x1?, 0xc00017e000)
	/home/steve/go/src/infini.sh/loadgen/loader.go:487 +0x566
main.startLoader(0xc00017e000)
	/home/steve/go/src/infini.sh/loadgen/main.go:107 +0x1af
main.runLoaderConfig(0xc00017e000)
	/home/steve/go/src/infini.sh/loadgen/main.go:443 +0x27
main.runDSL(0xc000557d40, {0xc00017c500, 0x49a})
	/home/steve/go/src/infini.sh/loadgen/main.go:434 +0xc5
main.runDSLFile(0xc000557d40, {0x7ffd275bad8d?, 0xc000174e90?})
	/home/steve/go/src/infini.sh/loadgen/main.go:429 +0x13a
main.main.func2.1()
	/home/steve/go/src/infini.sh/loadgen/main.go:373 +0xb0
created by main.main.func2 in goroutine 82
	/home/steve/go/src/infini.sh/loadgen/main.go:369 +0x56

And runner config entry skip_invalid_assert: true does let Loadgen skip invalid assert conditions