testsuite: add bc and dc tests

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/bc_misc1.bc

@@ -0,0 +1,76 @@
+define x(x) {
+	return(x)
+}
+define y() {
+	return;
+}
+define z() {
+	return ();
+}
+scale = 0
+x=2
+x[0]=3
+x
+x[0]
+scale
+ibase
+obase
+x ( 7 )
+x + x( 8 )
+x - x[0]
+321 * x
+2 ^ x[0]
+x++
+--x
+x += 9
+x
+length(2381)
+sqrt(9)
+scale(238.1)
+x=2
+x[0]=3
+(x)
+(x[0])
+(scale)
+(ibase)
+(obase)
+(x ( 7 ))
+(x + x( 8 ))
+(x - x[0])
+(321 * x)
+(2 ^ x[0])
+(x++)
+(--x)
+(x += 9)
+(length(2381))
+(sqrt(9))
+(scale(238.1))
+(scale = 0)
+(x = 10)
+(x += 100)
+(x -= 10)
+(x *= 10)
+(x /= 100)
+(x ^= 10)
+(x = sqrt(x))
+(x[1 - 1])
+x[(1 - 1)]
+2 + \
+3
+++ibase
+--ibase
+++obase
+--obase
+++last
+--last
+last
+last = 100
+last
+. = 150
+.
+++scale
+--scale
+y()
+z()
+2 + /*
+*/3