8288594: Address possibly lossy conversions in java.base FloatToDecimal

Reviewed-by: rriggs

Author: asotona

src/java.base/share/classes/jdk/internal/math/FloatToDecimal.java

@@ -356,7 +356,7 @@ private int toChars(int f, int e) {
          *     10^(H-1) <= f < 10^H
          *     fp 10^ep = f 10^(e-H) = 0.f 10^e
          */
-        f *= pow10(H - len);
+        f *= (int)pow10(H - len);
         e += len;
 
         /*