llcppgtest: test static lib

[MeteorsLiu]

​​Summary​​

llgo will introduce static library support, requiring new end-to-end tests in llcppgtest. These tests will validate static library compilation and linking by leveraging distinct import paths as specified in Issue #475.

​​Design​​

​​Import Path Distinction​​

Use zlib for dynamic library imports (existing).

Use zlibstatic for static library imports (new).

Test Example​​

// Test dynamic linking (existing)  
import _ "zlib"  
func TestDynamicLinkage(t *testing.T) {  
    // Validate dynamic library behavior  
}  

// Test static linking (new)  
import _ "zlibstatic"  
func TestStaticLinkage(t *testing.T) {  
    // Validate static library behavior  
}  

[luoliwoshang]

For llcppgtest -demos, what I actually want to do is avoid copying additional demos, meaning all import paths should use zlib. Otherwise, we would end up with multiple package names that are inconsistent, even though the actual content of the demos is the same. Does the current design seem to require making a copy of the demo?

[luoliwoshang]

homebrew or apt some libraries have not .a file and the e2etest can fully check the output's differentso we need not to check the static mode of llcppgtest 's demo test.