cmd/compile/internal/gc: unexport {J,S,F,H,B,V}conv

Updates #15462

Unexport Jconv, Sconv, Fconv, Hconv, Bconv, and VConv as they are
not referenced outside internal/gc.

Econv was only called by EType.String, so merge it into that method.

Change-Id: Iad9b06078eb513b85a03a43cd9eb9366477643d1
Reviewed-on: https://go-review.googlesource.com/22531
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/gc/bexport.go b/src/cmd/compile/internal/gc/bexport.go
index 5366262..24dfd81 100644
--- a/src/cmd/compile/internal/gc/bexport.go
+++ b/src/cmd/compile/internal/gc/bexport.go
@@ -355,7 +355,7 @@
 			// function has inlineable body:
 			// write index and body
 			if p.trace {
-				p.tracef("\n----\nfunc { %s }\n", Hconv(f.Inl, FmtSharp))
+				p.tracef("\n----\nfunc { %s }\n", hconv(f.Inl, FmtSharp))
 			}
 			p.int(i)
 			p.stmtList(f.Inl)