#154 cstage-only str== global-header miscompile (str== fast-path read the global str header off BP+0 instead of name(SB); byte-id 990-997 blind to a runtime-value miscompile). Lifted the run fixture into test/lang/strglobeq_test.ww (primitive @test value pin; byteid-eligible — post-fix cs==ww). byteid floor 55->56.