Disable EQUS expansion for raw symbols (by parsing them as strings) (#1648)

test/asm/raw-string-symbol-errors.asm

@@ -0,0 +1,29 @@
+def n equ 42
+def s equs "hello"
+macro m
+endm
+
+assert (#n) == 42
+assert (#s) == $656c6c6f
+assert (#m) == 0
+assert (#u) == 0
+
+assert strlen(#n) == 0
+assert strlen(#s) == 5
+assert strlen(#m) == 0
+assert strlen(#u) == 0
+
+def d_n = (#n)
+def d_s = (#s)
+def d_m = (#m)
+def d_u = (#u)
+
+def s_n equs #n
+def s_s equs #s
+def s_m equs #m
+def s_u equs #u
+
+purge #s
+purge #s
+assert (#s) == 0
+assert strlen(#s) == 0