mangle names in nimbase.h using cppDefine (#19395) [backport]

mangle names in nimbase.h
fix comments

tests/ccgbugs/tmangle.nim

@@ -0,0 +1,16 @@
+block:
+  proc hello() =
+    let NAN_INFINITY = 12
+    doAssert NAN_INFINITY == 12
+    let INF = "2.0"
+    doAssert INF == "2.0"
+    let NAN = 2.3
+    doAssert NAN == 2.3
+
+  hello()
+
+block:
+  proc hello(NAN: float) =
+    doAssert NAN == 2.0
+
+  hello(2.0)