v.trace_calls: now musl has gettid(), there is no need for the shim on newer Alpine etc (#24245)

vlib/v/tests/trace_calls_test.v

@@ -1,3 +1,4 @@
+// vtest build: !(os_id_ubuntu? && musl?)
 import os
 
 const vexe = @VEXE

vlib/v/trace_calls/tracing_calls_d_musl.v

@@ -1,8 +0,0 @@
-module trace_calls
-
-// gettid is missing on musl/alpine, but present on most everything else
-@[export: 'gettid']
-@[weak]
-fn vgettid() &u32 {
-	return 0
-}